In recent years, a peptide composition has been used in various applications. For example, there is known a peptide gel using a peptide having a self-assembling ability. The peptide gel has excellent mechanical strength and transparency, and hence has been used in various applications (for example, Patent Literature 1).
The peptide composition contains a buffering agent in some cases so as to be adjusted to a pH suited for an application. For example, there is a disclosure that, in preparation of a composition for cardiac tissue protection and regeneration, an acceptable buffer solution may be used to bring the composition to a physiologically acceptable pH (Patent Literature 2).